RFMD, Nujira team up for 4G broadband PA

Nujira and RF Micro Devices Inc. have jointly developed a broadbandpower amplifier (PA) design that covers seven Long Term Evolution (LTE) frequency bands as defined by 3GPP. The design integrates the new RFMD RFG1M family of high performance gallium nitride (GaN) amplifiers with Nujira's Coolteq.h envelope tracking power modulators.

Using just one RFG1M device with a Coolteq.h module, the RFMD Nujira RF front end transmits over a 728MHz to 960MHz band with over 50 per cent efficiency, and targets 4G base stations. Furthermore, using future GaN devices currently in development at RFMD, the two companies expect to cover the full range of the cellular frequency band from 700MHz to 2,600MHz with just three broadband PAs, allowing wireless infrastructure vendors to develop a single, highly-efficient multimode, broadband RF front end that can be deployed to meet various transmission standards anywhere in the world.

Lance Wilson, research director, RF components and systems, ABI Research, said, "Expect to see GaN, coupled with envelope tracking, in many new RRH designs. With a GaN/envelope tracking amplifier promising such high-efficiency operation, the Doherty circuit configuration can be disposed of and bandwidth will increase incrementally."

Commenting, Tim Haynes, CEO, Nujira said, "In partnership with RFMD, we have created a PA which covers the entire 700MHz to 1000MHz band without compromising on efficiency. Nujira's Coolteq modulators feature the only technology that can deliver this level of efficiency across such a broad bandwidth, extending the Software Defined Radio approach to the high-value power amplifier."

Bob Van Buskirk, president of RFMD's multi-market products group, said, "We see the combination of Envelope Tracking and RFMD's superior GaN devices and technology as a disruptive combination that changes the way base stations are designed."

According to Haynes, the joint design addresses a major issue in the 4G cellular base station market. "Infrastructure vendors are facing a portfolio management crisis, with more than 60 product variants needed to cover all worldwide frequency bands, cellular standards, and power levels," he said. "Even if they had the specialist engineering resources available to develop each product, the development costs and timescales would be prohibitive, with each and every variant costing hundreds of thousands of dollars to design, test, type approve, and qualify for production. We have delivered a high efficiency, broadband PA platform which can be deployed across multiple product variants, reducing time-to-market, development costs, and the cost of ownership associated with inventory management."